File 100-020b is a 60-m ASCII grid of depth data collected near Bank 66, East French Frigate Shoals in the Northwestern Hawaiian Islands as of May 2003. This grid has been produced as part of the "Bathymetric Atlas of the Northwestern Hawaiian Islands -- A Planning Document for Benthic Habitat Mapping -- Draft -- May 2003. Data sources for the downloadable grids include: multibeam bathymetry from Simrad EM1002 and EM120 sonars aboard the R/V Kilo Moana collected in October/November 2003; multibeam bathymetry data from a SeaBeam 210 sonar aboard the R/V Kai'imikai-O-Kanaloa collected in 2000-2002; LIDAR data obtained using the LADS MK II lidar system; and depth data derived from IKONOS satellite imagery. No tidal corrections have been applied to the data. The data source location for each type of data is indicated in the "dot plot" browse objects. Additional single-beam bathymetric data are available in this area and are indicated on the 100-020b Plot C browse object, but these less accurate depths are not included in the downloadable grid. Multibeam data were processed using SABER editing software and MBSystem and multibeam, LIDAR and IKONOS data were integrated using MBSystem, and GMT. Grid spacing is 60-m, horizontal accuracy is 20m (no differential GPS correctors applied), vertical accuracy is depth dependent (~1% of water depth), WGS84 datum. These data are not to be used for navigation.

Purpose:

The data provide baseline information about the location of bathymetric data that are available in the NWHI as of May 2003. The data have been synthesized as a starting point for formulation of a coordinated NOAA plan for future work in the area and as a guideline to data quality and usefulness for a variety of purposes, including coral reef analyses, reserve, sanctuaries and fisheries interests, and charting.

Horizontal accuracy is ~20 m as data were collected using GPS with no differential corrections. Vertical accuracy of data is data type and depth dependent; no tidal corrections were applied multibeam, IKONOS or single-beam data. Multibeam echosounder data are good to approximately 1% of water depth (depth ranges from ~10-5000m) ; IKONOS satellite depths are estimated to have a vertical accuracy of plus or minus 15 per cent; LIDAR data are accurate to IHO class 1 standards and are tide corrected.

Logical_Consistency_Report:

These data are believed to be logically consisten though no tests were performed

Simrad EM 120 (12 kHz) bathymetry and imagery data were collected in depths of ~100m and greater.
The EM 120 system was placed in stand-by mode in shallower water due to high noise levels.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Dr. Bruce Appelgate & Paul Johnson, University of Hawaii

Publication_Date: Unknown

Title: Simrad EM1002 Bathymetric Data

Type_of_Source_Media: Digital data

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2002

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: Simrad EM1002

Source_Contribution:

Simrad EM 1002 (95 kHz) bathymetry and imagery data were collected in depths of ~20-1000m.
The EM 1002 system was placed in stand-by mode in water depths greater than ~500 m.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Dr. John R. Smith, University of Hawaii

Publication_Date: Unknown

Title: SeaBeam 210 multibeam bathymetric data

Type_of_Source_Media: Digital data

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 2000

Ending_Date: 2002

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: SeaBeam 210

Source_Contribution:

The SeaBeam 210 multibeam sonar system is a hull-mounted, roll and pitch compensated
bathymetric deep seafloor mapping system capable of ensonifying a swath 70-80% of
the water depth. These data were used to plan and lay out the KM0206 multibeam surveys.
The SeaBeam bathymetric data, however, are of sufficient quality to provide depth information
that can be used for determination of the 25-, 50, and 100-fm boundaries.

Source_Information:

Source_Citation:

Citation_Information:

Originator:

Joyce E. Miller, Joint Institute for Marine and Atmospheric Research

Publication_Date: Unknown

Title: Simrad EK50 single-beam echosounder data

Type_of_Source_Media: Digital data

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 2001

Ending_Date: 2002

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: Simrad EK50

Source_Contribution:

The depth information was used to plan and layout the 25-fm survey lines, which facilitated
more efficient surveying. The QTC system is designed for use in bottom classification;
processing and analysis of the QTC information for benthic habitat mapping is on-going.

These data are not to be used for navigational purposes.
NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute
such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data,
nor as a result of the failure of these data to function on a particular system.